Safety device



i zy J- s. SAFETY DEVICE Filed June 11, 1946 Patented Aug. 14, 1951 JohnS. I

Page'Oil' nor of orma Rage, Long Beach, can, assignor to.

'I ools' lrrgt honig Beach; Calif; a 'corg Apnlicatiqn June 11, 1946,Serial No. 675,963

. 1 J This invention has to do with a safety device or safety plug ofthe break disc type -for u 'j 7 connection with vessels or element'shaxi'dl rig fluid pressure, and it is a general obJec't' of he inventionto provide an improved simple e'ffec-Q tive and dependable safety dvice'tagucuaay useful in connection with structures or elements such astanks; fluid handling ve sels, fluid op: erated tools, etc. Safety plugsof the break disc type have been long used inconnection with fluid prssur tperated devices or in oonn'ection'wi'th' elernents handlingfluidlpressure, 'and'the' usual device of this type involves abreak discof suitable strength held on a seat b'ya clamp, ring", 'or 'the'lik'efand 1 the seal established by means of a washengr the like, maintainedtight between'the disc and its seat or against the'front'si'de of thedisc by the clamp ring. Safety devices of the typeinention are notaltogether satisfactory since th ways subject to leakage, this being dueprimarily to the fact that the washereniiplo'yq'd, 19 K191515151? how itis arrange has no self sealing acti 'n t rather depends upon merepressure or. 91 mp1 g' action which holds both' the washer and disc.Leakage may occur in such an arrang F ment when the structure is Subjectto vibrati n or strain, or when it is subjectto shrinkage qr expansiondue to changes in ternperaturefTur thermore, leakage 'insuc 'aue e y 0'ur when there is the slightest shrink ge, deterioration of the w sher;

It is a general object of'my present invention to provide a safety decef' f the b eak d pe which involvesaself-sealing means or" ealingelement which doesnot dep'en'd'for' its s i action upon clampingpressure such as I ha referred to above. Another object of my presentinvention is to provide a safety deviceof he general' ch referred towhichinvolves a'sealin'g 'ineans t at acts effectively and de endablyand does not re; quire great skill or accuracy in the original set; tingor application as is the case wh r disc is sealed by rneans of the"usual washe arr:- rangement. In the structure that I'hav'e'providd Ihave eliminated entirelythe necessity fQf l mp m a t earupon theealme'element and the sealing element'that I a epm d'd acts effectively'guite regardl ss 9f thentanner in which the disc itself ma be mountedor held .l 1 A further object of my invention is t9 provide a safetydevice'of the generalicharacterre d to nvo vi g a ea i g. e ment we r:as he a1 in the desired manner when merely inserted into operatingposition and which involves a retainer for the sealing element which isvery simple and which serves to prevent accidental displacem'ent of thesealing element.

It is a further object of my invention to provide a sealing device ofthe general character referred to which includes a protective means atthe back of the sealingdisc which meansacts to prevent failure of thedisc in the Wei l of surge or momentary. back ressure'sueh asisenc'o'u'n teredi-n some hydraulic or fluid pressure handling t s n W,v The various objects and features of my invention will be fullyunderstoodfrom the following detailed description of typicalpreferredforms and applications of my invention, throughoutwhichdescripti'on reference is made to the ac: cornpanying drawings, inwhich:

Fig. "1' 'is a view showing a portion of a well tool subject to fluidpressure and showing the sa ftydevice of'my invention applied thereto;Fig. 2- is an'enlarged detailed sectional view taken as indicated'byline 2-2 on Fig. 1. Fig. 3 is a view taken as indicated by line 3-3 onFig. 2 and i is a'v'iw similar to Fig. 2 showing -another form of theinvention.

present invention is primarily concerned With asafet'y' dev'icelof thebreak discty'pe' and it -is' of'such character that it can be used to,advantage in connection with various devices, structures or elementshandling'or subject to fluid pressure. For instance, it can be used toadvantage in connection with cylinders'or flasks employed'to handleliquids or gases under pressure or it can be used in connection withtanks, cylinders or like vessels handling" or subject to fluid pressure,or it can be used in connection with tools subject to fluid pressure asfor instance in" connection with 011 well tools. Inthe draw-j ings 'Ihave, for sake of example, shown were. erit' invention applied intypical manners to an ele" em to be used in a well and which element issubject to fluid pressure. In Fig. l 'I have shown a portion of a welltool T involving a cylindrical body l 0 and the safety device S of myinvention is applied to the body ill within a recess lic In Figsfz and Ishow forni'of the in}; vention wherein the safety disc employed in thede c s s je to f i re hen exces iv es sure, is" applied to the exteriorof the body or elernent lliwhile in Fig. 4 of the drawings I Show a formwherein the safety disc is subjectto failure when excessive pressure,is: applied to the ever r the bod se en m In accordance with the broaderprinciples of my invention I provide a safety disc A to be supported ona seat B and I provide a seal or sealing means C that acts to preventleakage past or around the disc A. In practice I may employ, in

' addition to the parts named, a retainer D for the seal C and aprotector E for the disc A which elements I will hereafter describe indetail.

In carrying out my invention I may provide the disc supporting seat Bdirectly in the element subject to pressure. For example, directly in apart such as the body ill of tool '1'. However, I prefer to employ thegeneral type of construction used in safety devices of the break disctype, that is, I prefer to provide an opening [2 through the element orbody In which is subject to pressure and I apply a plug l3 to theopening E? which plug has a passage through it which passage is normallyclosed or obstructed by the break disc A. In the case illustrated I showthe plug it threaded into the opening 12 and I show a plug constructionproportioned so that a portion of the plug projects beyond the exteriorof the body i5 where the plug is provided with a head M formed andshaped to be engaged by a suitable operating tool. The particular headillustrated is polygonal in cross section so that it can be convenientlyengaged by a wrench and it projects far enough from the exterior of thebody it to facilitate easy manipulation of the plug in the course ofapplying it to or removing it from the opening [2. It is to be observedthat I have provided a tapered opening 12 and plug so that the plug canbe tightened into the opening so that there is no danger of leakagebetween these parts.

The passage through the plug l3 may be termed an escape passage since itallows escape of fluid when the break disc A fails, and in practice itmay be formed and proportioned in various manners. In accordance withthe preferred form of my invention the passage through the plu is formedby establishing two bores in the plug, a small bore [6 that extends intothe plug from one end and a large bore I! that extends into the plugfrom the other end. At a point within the plug or intermediate its endsthe seat B occurs where the bores vice is to fail under pressure fromthe exterior of the member II] the small bore Li enters the plug fromits inner end while the large bore ll enters the plug from its outer endwith the result that the seat B faces outwardly in the plug. It will beapparent that by establishing the desired differential in size betweenthe bores l5 and I? the desired fit or a seat necessary to hold the discA can be established.

The break disc A may be an ordinary suitable break disc such as iscommonly employed in devices of this general type, that is, it may be asimple plain or fiat disc of material, say for instance, sheet metal orcast metal, or of any other suitable material having its thicknessrelated to its size so that it fails when subject to a predeterminedpressure. In accordance with my invention I preferably apply the breakdisc A directly to the seat B so that there is direct bearing engagementbetween these parts as shown in the drawings, and I make the disc A of asize or diameter so that it will slidably fit into the opening H so thatit can be conveniently slid into operating position.

The seal C which I have provided involves, primarily, a disc-shaped bodyof sealing material which I will term a bottom 20 that preferably l6 andI! join. Where the de-..

bears against the outer side 2| of the disc A, and an annular part orside wall 22 which projects outwardly from the bottom 20. I prefer toform the bottom 20 and side wall 22 of the seal C integrally so thatthese parts together form a cuplike element and, in accordance with myinvention I form these parts of a conformable or elastic material,preferably rubber or a rubber-like composition. I make the exterior 23of the bottom 20 so that it seats on or bears against the outer side 2|of the disc A and I make the exterior 25 of the side wall 22 cylindricaland smooth and so proportioned relative to the large bore I! as to fitsnugly therein. In fact, Lprefer to proportion the seal to the bore I!so that it fits tight enough to require some pressure for insertion intooperating position, as shown in the drawings. When in operating positionthe fit of the seal in the bore l1 establishes an initial or normalsealing engagement between the side wall 22 and the: bore H. Because ofthe cup-shaped construction. or formation of the seal C pressure on theseal. admitted through the bore ll serves to press the: bottom 2% of theseal tight against the disc A. thus communicating the pressure to thedisc A. tending to push the disc out through the small: bore Ha. Suchpressure on the seal acts radially outward on the wall 22 forcing thewall into tight: sealing engagement with the wall of the bore 11,. thuspreventing leakage through the structure. It will be apparent that aspressure increaseson the seal the wall 22 is merely pressed tighter inthe bore I! while the bottom 20 presses against the disc A until finallythe disc fails, at which. time the bottom 20, being without the support.of the disc, likewise fails, to the end that the;

passage is open through the plug allowing escape.-

of pressure.

The retainer D that I prefer to employ may be seal in the bore may besufficient to hold it in. place, making a retainer unnecessary. Thepre-- ferred form of retainer, as illustrated in the draw-- ings,involves a split ring 30 carried in a groove 3! provided in the wall ofbore l1 outward of. the side wall 22 of the seal C or between the end ofwall 22 and the entrance to the bore IT. The simple snap ring that Ihave illustrated is inexpensive and can be easily applied and yet servesas an effective means to retain the seal in place.

The protective means E may or may not be used, as circumstance require.I provide the protective means E at the inner end of the passage throughthe plug or at the side of the safety disc opposite to that at which theseal C is located. The protective means acts mainly to prevent surge offluid or a reverse pressure that would cause excess pressure on theinner side of the disc A from dislodging the disc A from the seat B. Itis to be observed that with my construction the sealing disc A might bedislodged from seat B in the event excess pressure developed on the discA through the small bore l6. To eliminate such a hazard I preferablyprovide the means E which may be in the form of a closure forthe boreHi. In the case illustrated the means E involves a plug 40 carried inthe bore l6 and having a head 4! bearing on the inner end of the plug13. As I have illustrated the plug may be screw threaded into the boreI6. The.plug 4i] and its head may be integrally formed and may be formedof a material that will fail under high pressure or under a givenpressure. For instance,

in practice this part of the structure may be formed of a plastic orcomposition such as a hard rubber composition or the like. Byconstructing the means E in the manner illustrated it will be apparentthat it is-efiective in checking excess or abnormal pressure that mightotherwise dislodge the disc A and yet it will not interfere with escapeof fluid through the structure when the disc A fails. It is to beunderstood that the plug 41! is made of a material or is so mounted thatit fails or is dislodged when the disc A fails by reason of pressureentering the structure through the bore H.

In the form of the invention shown in Fig. 4 the various parts that Ihave referred to are present except that the arrangement is reversed,that is, I show an arrangement wherein the small bore [6* in the plug l3enters the plug from the head end rather than from its inner end, whilethe large bore l'l enters the plug l3 from the inner end rather thanfrom the head end. In this arrangement the seat B faces the inner end ofthe plug instead of the head end of the plug and, consequently, the discA seats outwardly in the plug instead of inwardly therein. The means A,B and C in this case may :be identical with that above described as wellas the means D and the means E if they are employed. In this form of theinvention the action of the structure is the same as that abovedescribed except of course that the disc A is subject to failure upon apredetermined pressure entering the plug l3 from its inner end ratherthan from its outer end.

Having described only typical preferred forms and application of myinvention, I do not wish to be limited or restricted to the specificdetails herein set forth, but wish to reserve to myself any variationsor modifications that may appear to those skilled in the art and fallwithin the scope of the following claims:

Having described my invention, I claim:

1. In a structure of the character described an element subject topressure and having an opening therethrough with pressure on one endthereof, there being a seat in the opening facing in the direction fromwhich the pressure is exerted, a break disc carried by the seat and heldthereon by said pressure, and an expansible cup shaped seal carried inthe opening supported on the pressure side of the disc and having a sidepart held in sealing engagement with the wall of the said pressureopening.

2. In a structure of the character described an element subject topressure and having an opening therethrough with such pressure at oneend thereof, there being a seat in the opening facing said end of theopening, a break disc carried by the seat, a cup shaped seal carried inthe opening having a disc-shaped bottom supported on the disc and havingan expansible cylindrical side wall having sealing engagement with thewall of the opening, and a retainer holding the seal in the opening.

3. A device of the character described including a plug for holdingpressure and having a small outlet bore extending into it from itspressure holding end and a large inlet bore extending into it from theother end establishing a seat in the plug intermediate its end, a breakdisc arranged in the large bore to be supported by the seat and subjectto pressure admitted by the large bore, and a seal slidable in the largebore and subject to pressure admitted by the large bore and having asealing portion held in sealing engagement with the wall of the largebore by pressure acting toward the seat.

4. A device of the character described including a plug having a smallbore extending into it from one end and a large bore extending into itfrom the other end establishing a seat in the plug intermediate its end,a break disc arranged in the large bore to be supported by the seat, anda cup shaped rubber seal in the large bore having a bottom bearing onthe disc and a sealing side wall held in sealing engagement with thelarge bore by pressure acting toward the seat.

JOHN S. PAGE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

